This invention relates to rocker type electric switches, and more particularly to a rocker type electric switch designed for automotive application, such as for use to control the flow of current to the heating elements of a rear window defogger.
Rocker type electric switches are known in the prior art. They have the advantage of being cheaper to construct than other types of switches but they also have faults. One such fault found in the rocker switches of the prior art is that the switch will close too soon, and uncontrollably, following initial actuation of the knob that is pressed to open or close the switch. In prior art switches, of the rocker type, the switch contact element is freely movable to closed position in response to pressure thereon by the actuating plunger when the knob is pressed. Therefore the switch contact element can close uncontrollably, at any position of the knob and plunger, as soon as the knob is pressed. This fault may result in the switch closing when the knob is touched accidentally, with no intent to operate the switch, and it also tends to cause more frequent "welding" of the switch contacts in closed position as a result of arcing between the contacts at the time the switch closes, before it comes into fully closed position.
Prior art type rocker switches have been provided with lugs or similar means for assuring opening of the switch at a particular position of the actuating knob. But the prior art does not disclose the combination of the present invention whereby quick, positive and forceful switch closing at a particular knob position is provided, in addition to positive switch opening.
Examples of rocker type switches known in the prior art are shown in the following U.S. Pat. Nos. 2,874,338; 2,927,983; 3,646,291; 3,852,557.